Record UMA stats for Blink decoded image types

Source/platform/image-decoders/jpeg/JPEGImageDecoder.h

Index: Source/platform/image-decoders/jpeg/JPEGImageDecoder.h
diff --git a/Source/platform/image-decoders/jpeg/JPEGImageDecoder.h b/Source/platform/image-decoders/jpeg/JPEGImageDecoder.h
index ceb44f5b5e7c91bc1d16dbebaaeed74522e1c592..629c8aa3c05dc3b68e9fa8dae5350dda4a845579 100644
--- a/Source/platform/image-decoders/jpeg/JPEGImageDecoder.h
+++ b/Source/platform/image-decoders/jpeg/JPEGImageDecoder.h
@@ -64,7 +64,11 @@ public:
 
 private:
     // ImageDecoder:
-    void decodeSize() override { decode(true); }
+    void decodeSize() override
+    {
+        decode(true);
+        reportStats(ImageJPEG);
+    }
     void decode(size_t) override { decode(false); }
 
     // Decodes the image.  If |onlySize| is true, stops decoding after